Plug nozzle rocket engines are common engines in the field of rocket, missile, and space vehicle propulsion. The exhaust flow from a conventional annular plug nozzle throat is largely symmetrical and not easily redirected for the purpose of altering the thrust vector to control attitude or direction of the vehicle on which the engine is mounted.
Traditionally, angular displacement of a thrust vector has required angular displacement of the entire rocket engine. For example, one type of thrust vector control system is a gimbaled thruster. The gimbaled thruster moves about a point of rotation relative to the vehicle on which it is mounted to redirect the thrust vector of the vehicle. This system requires precise gimballing mechanisms. These mechanisms are exposed to large forces, require high power to achieve rapid response, are heavy, complex, and costly.
Another thrust vector control system includes a plurality of thrusters arranged at angles diverging to opposite sides of a vehicle. For example, see U.S. Pat. No. 4,384,690, entitled “Thrust Vector Control for Large Deflection Angles,” issued to Broderson. A supply of thrust producing gas is ducted to the thrusters from a gas generator via ducts. A guidance system provides control signals to those valves to effect pulse duration modulations of the thrusters. The combined vector of the total axial thrust is the sum of the axial components of all of the individual thrust vectors from the plurality of thrusters. This system is complicated and expensive.
Therefore, there exists a need for an improved plug nozzle rocket engine having a reliable, fast response, low power, low mass, low cost, rapid, effective, and simple mechanism for altering the thrust vector of the engine.